Mean Maximal Power: A Unique Comparison

It's been a while since I posted. Just too busy for the most part so my apologies.  I'll do an update at some stage!

I had a long break from training due to a prosthetic leg changeover in June (had a few transition problems with that) and a lot of travel in August and September. I've been back on the bike for a few weeks now (the hardest part sometimes).  I sure have some fitness to catch up on.

For some personal motivation, I thought I'd post up a couple of charts comparing my performance before and after the leg amputation (I get asked about it occasionally, and my data is being analysed for a science write up at the moment).

So I thought I would summarise it in a neat chart known as a Mean Maximal Power (MMP) chart.

MMP charts show your best power ouput for all durations from very short periods (seconds) through to very long periods (hours). Because the horizontal axis represents durations from second to minutes to hours, we turn that into a logarithmic scale, so we can inspect best power outputs for durations covering a wide time spectrum.  Power is represented on the vertical axis.

As you would expect, one can produce higher power for short periods (seconds), and somewhat lower power over longer periods (hours), so the chart trends downwards as you move to the longer durations on the right.

By using WKO+ software, I made a comparison of my all time personal best power for the time before my accident and amputation and since then.

Two versions plotting mean maximal power to weight ratios, one for Average Power and one for Normalised Power. The blue line is before amputation, the red line is since then.

Click on the chart to see a full sized version:

The chart above shows my best W/kg for all durations. 

What is very clear from that chart is the wide performance gap for very short durations but the closeness in performance over durations longer than a minute or so.  This suggests my sustainable aerobic power and my anaerobic work capacity hasn't been significantly hampered by riding with a prosthetic, however my neuromuscular power (used for sprinting and short duration hard accelerations and efforts) has been significantly compromised.

What about Normalised Power?

When plotting NP data, WKO+ restricts the output to a minimum of 5-minutes.  For most analysis and application, we really don't read too much into NP for durations shorter than about 20- to 30-minutes.  But nonetheless, the chart shows an interesting change in my power profile when viewed through the lens of Normalised Power.

NP appears to amplify the difference in performance over a wider part of the primarily aerobic duration spectrum (> 5-minutes) when compared with the Average Power chart

A reduction in my ability to perform those short high power bursts (up to ~ 30 seconds or so) definitely comes though in the NP for durations from 5- minutes to about 30-minutes.

For longer durations than half an hour though, I have been able to equal or somewhat exceed my best pre-amputation NP outputs.

This I think is reflective of the type of racing I do - which is lots of track and crit racing, some road races and only occasional time trials.  So for an apples to apples comparison, I certainly think this NP chart is pretty telling.

I no longer have that weapon of short high end power, but have instead found other ways to make up for it.

Of course this is just one way to use MMP charts. Once can plot one season over another and make comparisons as to their overall progress. Or any time periods they care to compare.

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l'Alpe d'Huez - one for the mortals

About this time last year I posted this item about ascent times of leading professional riders up l'Alpe d'Huez and what power to body mass ratio would be required to do that.

There's a chart which shows the relationship between ascent time and power to body mass ratio (watts per kg - W/kg). It also provides an indication the impact of wind can have on climbing speeds.

Times for leading riders since 2001 are shown on the chart.

The guys over at the Science of Sport blog referenced it in a post here, after seeing it on a cycling chat forum I posted to recently.

Well for a bit of fun (and considering the Tour de France is heading up the Alpe in a few days), I thought I'd post a follow up chart which covers the power to body mass ratio for the rest of us mere mortals.

Here it is (click to embiggen):


It's not a hard chart to read.

Want to ride up l'Alpe d'Huez in 1 hour dead? Then you'll need to be able to sustain around 3.75 W/kg, give or take depending on the wind. If you are 70kg, then that's around 260-265 watts.

If you know your sustainable power is 3.4W/kg, then you can expect to get up the Alpe in around 66 minutes.

In calculating these values, I've made a few assumptions (listed on the chart), although the relationship between speed and W/kg on steep climbs is not particularly sensitive to those assumptions.

After power and mass, wind has the biggest impact on speeds when climbing. Hence the two extra lines for head and tailwinds.

At my best form*, I would expect to climb it in around 56 minutes.

How fast have you been up l'Alpe?


* My power to body mass ratio for 1-hour at best is ~ 4.2W/kg (based on my racing power at the UCI World Cup this year), but I have to allow a bit of extra mass for my prosthetic leg. I'll get to do it one day.

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Aero Profiling

Earlier this week I posted this item about power to aerodynamic drag ratio for the individual pursuit.

I mentioned in that item a table prepared some time back by Andy Coggan, which was similar to his power profiling table (which lists typical power to body mass of riders - W/kg for various time ), except it showed Functional Threshold Power (FTP) relative to aerodynamic drag (CdA) - W/m^2, instead of as per the original power profiling table.

The top end of the table would represent what's required to set a World Best Hour record.

In this way, a rider's power to aero drag ratio can be compared against the world's best.

Andy has kindly sent me the data, so here is the table for reference. Thanks Andy.

Enjoy!
(click on the pic to superaeronate)

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Individual Pursuit - What Makes us Faster?

A long time ago, in a galaxy far away, a Jedi Knight called Andy Coggan developed an insightful (but often misunderstood) table of numbers known as Power Profiling. Power junkie cyclists have been (mis)using the table to psych out their mates for years now.

The Power Profiling table lists power to body mass ratios for four key durations: 1-hour, 5-minutes, 1-minute and 5-seconds, chosen to reasonably represent the energy systems/physiology that predominantly underpin performance over these duration, i.e. (respectively): lactate threshold, maximal oxygen uptake (VO2max), anaerobic work capacity & neuromuscular power.

Power to body mass ratio is an excellent overall predictor of performance potential. It is especially good for determining performance when climbing hills.

However, performance in flatter time trials and individual pursuits is much more a function of power and aerodynamics than it is of power and body mass. Body mass of course impacts aerodynamics, however the relationship between them is variable, with overall morphology and position on a bike far more influential than body mass per se.

So, when choosing the one performance factor most important for flatter time trials and pursuits, one needs to focus on improving a different ratio – the Power to Aerodynamic Drag* ratio (power to CdA ratio - W/m^2).

The higher the W/m^2, the faster we go. Pretty simple really.

In 2009 Jedi Knight Coggan, being somewhat prescient, developed a draft version of his power profiling table, this time expressing performance in terms of the ratio of 1-hour power to CdA . I’d love to share a link to it, but I’m not sure I have a public location I can point you to (it was originally posted on a discussion forum about two years ago which has suckerific search function). I’m sure either Andy will provide a link, or post up a new blog item about it at some stage.

In any case, I thought at the time it might also be of interest to develop a similar table for the Individual Pursuit, so Andy whipped up one for me, and I then took that data and created a chart and table. Now that was nearly two years ago and I've been meaning to do a blog post about it ever since! Okay, so it's a little late but here it is.

The table show times for 2km, 3km and 4km individual pursuits and the corresponding W/m^2 required to attain that performance (click / right click to show full sized version):


So, for example, if you want to ride a 3km pursuit in 3:35, you will need a power to aero drag ratio of about 1900 W/m^2.

Alternatively, if you know your power and pursuit time (on a fast track), then you can back calculate an estimate of your CdA. e.g. a rider who completes a 4km pursuit in 4:30 requires a power to aero drag ratio of ~ 2200W/m^2.

If we know their power output we can then estimate their CdA. Let’s say they averaged 480W.
CdA = (480W) / (2200W/m^2) = ~ 0.218 m^2

It’s not perfect of course, just a guide and there are many factors to consider. Besides, if you have a power meter on your track bike, there are better ways to determine your CdA.

The chart below plots the same data, as well as show where on the chart the current world record holders appear for the following categories:

Elite Men & Women
Junior Men & Women
Masters Women

Hence, these world records represent the current upper limit of W/m^2 for each category:


The records are from the UCI website here: Track World Records

With the exception of Sarah Hammer’s WR in Aguascalientes, all of the others were set at sea level and in indoor velodromes (and so the assumptions used for the table data will be closer to the mark).

In the case of Sarah Hammer, due to the significantly reduced air density at altitude, it is probable her W/m^2 is overstated and is a little less than previous world record holder Sarah Ulmer whose record was set at sea level. The Power/CdA estimate for Ulmer’s 3:24.537 ride is 2200 W/m^2.

One thing the chart emphasises is just how much one needs to improve W/m^2 in order just to go even just a few seconds faster. When you are near your physiological performance (power) limit, we can see how important aerodynamics are to overall performance.

And just how freakin good those world record rides are.


Now of course there are some assumptions used to make up the data for the tables (assumption are shown on the table and chart). For example, it does assume a pretty fast track/tyres at a typical sea level air density, but really it’s just a guide, and serves to emphasise the importance of aerodynamics and thinking in terms of W/m^2 when working out what to focus on to improve your pursuit and time trial performance.

If your track and/or tyres are slower than the best, then it’s likely the performance suggested as attainable from a given power to aero drag ratio is overstated (or the W/m^2 required for a given performance is understated). Also, the rate of change in kinetic energy and associated variable power demands will also have some impact on these estimates. These data have used typical assumptions for that, but of course everyone’s initial acceleration, mass and fade in speed during their pursuit rides are different.

I’ll look into doing a similar chart for the hour record at some stage.

Where do you fall on the table?


For those interested in more discussion on factors impacting pursuit performance, then these items by Andy Coggan are a great place to start:

Demands of the individual pursuit, part 1
Demands of the individual pursuit, part 2



* Aerodynamic Drag is expressed as the combination of our two factors:

- Coefficient of Drag (Cd), a unit-less measure which is related to the shape of an object and how that affects air flow around it (e.g. think of a brick vs a bullet shape, the bullet shape has a lower Cd); and

- Effective Frontal Area (A), measured in square metres (m^2) which is how much area we present to the air (e.g . compare a van and a Mack truck – the truck has a larger frontal area and has to push more air).

These two factors are multiplied together to determine how "slippery" we are through the air.

Some example typical CdA values:
Commuter cyclist: 0.4 – 0.7 m^2
Road racing cyclist: 0.26 - 0.38 m^2
Time trial/pursuit rider: 0.2 – 0.3 m^2
Sports car: 0.5 - 0.6 m^2

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Winners never quit

It’s one of those phrases you see on “motivational posters” about the place. I’ve never really had such posters hanging up. I suppose I’ve never really felt the need to have such things to motivate me, although some of them are quite good pictures.

I certainly never ever thought I’d be in one of those pictures or be someone to inspire others.

Nevertheless, I seem to have found myself in that position – after a friend and mentor sent me the picture above.

I’m not hard to pick out of course (just play spot the carbon leg) but for those interested – the shot is of my race winning sprint in the Eddie Salas Cup on 8 May 2011. It was an A-grade Masters circuit road race at Sydney’s Eastern Creek raceway. 60-70 starters. There were over 200 racing that day in all grades.

It was a cold morning (for Sydney about 6-7 C) and a foggy start. The race was the usual affair with break attempts, counters and so on. I bridged across solo to one such break, which I thought looked dangerous, but it was brought back.

A cool foggy morning, and the pace was on...

Then with about 25-min to go, I just knew I was feeling good and said to myself that I had a threshold effort in me for the balance of the race. There were some riders up the road. So I decided on the last hill before the main straight to push hard off the front of the chasing group. Only one rider (Matt from Sydney CC) was on my wheel, so I put my head down and buried it. He worked with me but eventually faded so I kicked on and finished off the bridge across solo. It was about 2.5-3-min effort at 350W.

The bridge across, Matt was suffering, I was ready to launch again.

Now I was there I had to consolidate, which I managed OK, then did some work with them to establish the break – they were riding hard. Since two of us had either club or team mates in the group behind, we had a combination that just might stick. I knew that if we got caught, all it would mean was my team mates being dragged to the front of the race and being in a great position to finish it off – being in a team makes such a difference to race tactics, it’s way cool to race this way.

The break, and rolling off after a turn

Once I was convinced we were not going to get caught, I started to reduce my workload, while the other two kept pushing hard. Fine by me, I just sat on (mind you my NP for the final 30-min of race was 331W so it wasn’t exactly a walk in the park).

Then the finishing straight was upon us and I was very patient, waited as long as I thought I should, gave myself some room to run at the wheel in front and gave it what I had.

I won. By about 10cm. That’s enough. :-)

Winners are grinners they say.
Eddie Salas finished 4th - he's on the right in the blue and my team mate Matt 5th.

Massive thanks to the rest of Team Turbo Studio. We might have stern looks on our faces in the promotional shots (a la the Sopranos), but we sure smile when out there racing, and especially when we have the podium stuck to the soles of our shoes.

It ended off a great week with four big races, some really good form and my third race win of the year.

I wrote in my previous post about the UCI World Cup road race. Well in between that and the Eddie Salas race I raced the UCI World Cup Paracycling time trial on a technical circuit at Sydney Olympic Park.

It was 4 laps, which meant riders from various categories were on the circuit at the same time. Technical suited me as I’m a pretty decent bike handler but it meant some interesting tactics were needed. Whenever I came up behind another rider, I would surge to get past them before the next corner as most of the other riders were too slow through the turns and would hold you up.

In the end I placed 7th overall and was the fastest of the three Australian C4 riders, 4-seconds faster than National TT champ and Aussie squad rider Ryan Hughes. I was second fastest Aussie overall behind Michael Gallagher in the C5 category.

Average Power for the 32-minutes was 320W, so that’s not too shabby at all and I was very pleased to have had the opportunity to race my first international UCI paracylcing event, and to race well and be competitive.



But back to that picture.

It’s never been my objective to inspire others – I simply love racing my bike, so do what I can within the constraints of my life to improve my own performance and to race. I've had plenty of support as well from many people. Still, I am proud of what I’ve been able to achieve in the four years since my accident and amputation. If that inspires others, that’s pretty cool I guess and I can live with that.

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World Cup – Road Race

Today I raced my first UCI World Cup event – it was a ~75km road race with C4 & C5 para-cycling categories combined. Being held at the Eastern Creek Raceway and Western Sydney International Dragway circuit, (similar but not exactly the same as the circuit used last year for the World Masters Games) meant I had some home town knowledge of what I was in for since I have raced on both these venues.

What I didn’t know of course was how the competition would be. I knew one of our Aussie riders – Michael Gallagher – would be pretty hard for anyone to beat as he is a world class athlete but other than that, I wasn’t really sure of the field.

Conditions were good: cool, dry and sunny with a south to SW breeze. Sure made for a nice change with the rain we've had lately. I did 6 turbo session in the previous week.

In the end I came 4th in the C4 category, and my compatriot Ryan Hughes 3rd. Michael Gallagher came 2nd in the C5. That was perfect as the Aussie team plan was for Michael (C5) and Ryan (C4) to finish as high as possible and gain extra points for the world championship qualification places.

I had good legs today and some pretty decent numbers:
Ride time: 1:54
Normalised Power: 302W

When the race was pretty fiesty, I had a 30-minute NP of 327W.

The Italians dominated, and after the opening lap the fireworks started with plenty of attacks and counters. Eventually the break formed with 3 Italians, Michael Gallagher and 2 others. Since Mick was up the road we had no real reason to chase, next job was to get Ryan Hughes placed as high as possible, so helped him out here and there. My legs were good today – I sure felt pretty good.

I thought about going with the Italians early but they were very strong and it was a very tough place to be burning a big match. When the chase to the main break attempt was on, someone baulked as we were closing in and that didn’t help. Then a rider (the Canadian I think) crashed in front of me at the left hand turn entering the main raceway. That took all the momentum out of the chase. After that it was a training ride for next 4 laps, then in last 1.5-2 laps the group started getting frisky looking to get the minor placings.

I chased down one break by the British rider late in the race, and was about to do it again when the call was to let him go as he was C5. I certainly had the legs to go if needed.

Heading into the finale I was getting ready to go to front to give Ryan a lead out along with Mitchell Gourley from St Kilda, when the Italian for some reason let a gap go for Ryan and Mitch, and so they went for it with about 1.5km to go. I then just sat on the Austrian, Italian, and the American (Sam - of course! I said g’day during the race and asked his name) until the sprint as they were now chasing the Aussies. Fine by me.

Sam the American opened it up at top of straight, the Austrian was cooked and the Italian had nothing left or couldn’t be bothered (they were both on the front a lot today) so I went and eventually overhauled Sam down the long finishing straight, was catching Ryan and crossed line as 4th placed C4, and 8th overall.

Pretty darn happy with that. I’ve gone from having a lower leg amputation to a World Cup result in a bit less than 4 years.

Time Trial is on Friday. It’s technical and well I’ll just let ‘er rip and see what happens.

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New Team

Last weekend I had a tune-up race at Eastern Creek. Mainly to have a good hit out and also to ride over part of the circuit that will be used for the UCI World Cup event in early May. I had a puncture which interrupted proceedings for a while but a wheel change saw me back into it and doing my best to put myself in the hurt box often.

Attacks and covers didn't pay off results wise but that didn't matter. I didn't quite make it across to the attack that actually stuck, which featured Eddie Salas, Pete Milostic and Trent Butler. Go figure.

Still, a few silly solo efforts and big pulls on/near the front practicing a few things meant a great hit out.

1hr:22min with Normaised Power of 302W, so not too shabby.

Since then been training pretty solidly, some good longer rides and also started some higher intensity work at around 90% of Maximal Aerobic Power or 120% of threshold power. Nasty buggers those. We call them Aerobic Power Intervals (APIs).

Plenty of racing for me coming over the next few weeks. On the agenda are:

30 Apr: Cervelo Masters Series Round 1 (64km Kermesse)

4 May: UCI Paracycling Road World Cup - 78km road race at combined Eastern Creek Raceway - Sydney Dragway circuit

6 May - UCI Paracycling Road World Cup - 25km Individual Time Trial

8 May - Eddie Salas Mother's Day Cup (75-min + 1 lap)

14 May - NSW State Masters Road Race Championships

15 May - NSW State Masters Criterium Championships

Then in June there is the remaining three races of the four round Cervelo Masters Series.

All of course will be in my new team race kit, and the non-championship races (Cervelo & Salas races) we will be racing as a full squad, which will be uber cool. We all had a full squad practice run together a month back at the Orica Kermesse where we got two of our team up on the podium, so that was a good start.

The lads have been in fine form, with everyone getting results over the past couple of months.

And here's the link to introduce the new race team. Watch out Sopranos, you ain't got nuthin' on us!

Turbo Studio Masters Race Team

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